Prior art pressurized fuselage doors are not a structural part of the fuselage, in that they do not carry any of the hoop tension caused by cabin pressure. Rather, the hoop tension is carried around the door in the door jamb structure, requiring extra weight because of the stress concentration around the hole in the fuselage. The internal pressure on the door causes a bending moment in the door, requiring a substantial and heavy door structure.
Much of this weight and complication could be eliminated if hoop stress could be transferred through the door structure. The prior art, however, shows no simple and reliable method for doing this.
Accordingly, an object of the invention is to provide a pressurized fuselage door for aircraft which is lighter and simpler than the prior art and which enables a lighter surrounding fuselage structure.
A further object of the invention is to provide a reliable method of carrying hoop stress through a hatch in a pressure vessel without complicated linkages.
A further object of the invention is to provide a door operable in highly curved or complex curved fuselages.
The above as well as additional objects, features, and advantages of the invention will become apparent in the following detailed description.